A hydraulic driving device may be used in a steam turbine for driving a steam valve (for example, a stop valve, a regulating valve, or the like) used for shutting off a steam flow and controlling a steam flowrate.
For example, Patent Document 1 discloses a steam valve including a stop valve driven by a valve driving mechanism using a hydraulic cylinder. In the steam valve, output shafts of a plurality of hydraulic cylinders are connected to a valve shaft of a stop valve via a connection member. The valve shaft, with which a valve body of the stop valve is operated, is driven by the plurality of hydraulic cylinders via the connection members. A plurality of hydraulic cylinder mechanisms are synchronously driven under control performed by a control device.